Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered; the description adds the non-obvious quota-cost disclosure 'Does not spend quota', which is not derivable from annotations. It also frames the operation as 'private' and 'caller-scoped', reinforcing the idempotentHint. It does not disclose rate limits or whether outputs are cached.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, front-loaded with the identity and the trigger phrase before the output list. The middle sentence is a dense comma-separated enumeration but each item is meaningful. No filler padding.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be restated, and annotations cover the safety/idempotency profile. The description supplies the trigger, the free-usage constraint, and caller scoping, leaving little an agent needs. The one gap is disambiguation from the parallel zambo_universal entry point.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and all four optional underscore-prefixed parameters carry their own descriptions, so the schema does the heavy lifting. The description adds nothing about the parameters (no mention of session, key, or continuity labels), which is acceptable at full coverage but earns only the baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description goes beyond the vague marketing line 'Your private Zambo starting point' to specify concrete outputs: a welcome, job resumption, today's saved receipt links, per-tool free usage, and three next actions. That is a clear, specific resource. It does not, however, differentiate itself from the sibling zambo_universal or explain what makes 'home' distinct from a universal entry point.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives an explicit trigger ('Use when the user says "zambo"') and two use conditions (welcome new users, resume the same caller-scoped job). It states no when-not conditions and names no alternative sibling, so routing against zambo_universal is left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.